This invention relates generally to portable manually held saws and more particularly to a drive tensioner for applying tension to the flexible means drive members for such lightweight portable saws.
Lightweight portable saws which have an engine that drives a saw blade have gained widespread use in a number of applications. One such type saw uses a reinforced circular abrasive type blade which can cut concrete, metal and other materials. The circular blade is drivingly connected to the engine through a belt or chain drive to rotate same. The circular blades must be rotated within a given speed range in order to get the blade to cut properly and not be damaged. Because of space requirements, the speed variation that can be achieved between that of the engine and that of the cutting blade is limited. This has created manufacturing problems since it is frequently more economically feasible to obtain engines with dramatically different speeds to power the saw. Heretofore, attempts to match engine speed with circular saw blade speed has been difficult to achieve over a broad range.